TY - JOUR

T1 - Effect of Ni non-stoichiometry on the structural, thermal and conductivity properties of Nd2Ni1-xO4+δ

AU - Naumov, Sergey V.

AU - Vlasov, Maxim I.

AU - Pikalova, E. Yu.

AU - Tsvinkinberg, Victor A.

AU - Reznitskikh, Olga G.

AU - Filonova, Elena A.

N1 - Текст о финансировании #1 This work was supported by the state assignment of Ministry of Science and Higher Education of the Russian Federation (theme “Spin” No. 122021000036-3 and No. 122020100324-3 ). Investigation of thermal properties was carried out within the framework of the state target of the Institute of Solid State Chemistry, Urals Branch, Russian Academy of Sciences, the topic no. 0320-2019-0005 (reg. no. NIOKTR АААА-А19-119102990044-6). The authors are grateful to Mr. Nikita S. Ermolov (Ural Federal University, Yekaterinburg, Russia) for the help with synthesis of the materials for the study, Mr. Sergey M. Pikalov (Institute of Metallurgy UB RAS, Yekaterinburg, Russia) for the help with providing of XRD experiments, and Dr. Artem Gilev (Ural Federal University, Yekaterinburg, Russia) for the fruitful discussion of the defect model. Текст о финансировании #2 This work was supported by the state assignment of Ministry of Science and Higher Education of the Russian Federation (theme “Spin” No. 122021000036-3 and No. 122020100324-3). Investigation of thermal properties was carried out within the framework of the state target of the Institute of Solid State Chemistry, Urals Branch, Russian Academy of Sciences, the topic no. 0320-2019-0005 (reg. no. NIOKTR АААА-А19-119102990044-6). The authors are grateful to Mr. Nikita S. Ermolov (Ural Federal University, Yekaterinburg, Russia) for the help with synthesis of the materials for the study, Mr. Sergey M. Pikalov (Institute of Metallurgy UB RAS, Yekaterinburg, Russia) for the help with providing of XRD experiments, and Dr. Artem Gilev (Ural Federal University, Yekaterinburg, Russia) for the fruitful discussion of the defect model.

PY - 2023

Y1 - 2023

N2 - Neodymium nickelates Nd2Ni1-xO4+δ with Ni non-stoichiometry, varied in a wide x range of 0.0–0.08, are synthesized for the first time, and their properties are studied depending on the Ni content. The limit of Ni deficiency is found to reach 6%. According to the XRD data, the materials of the Nd2Ni1-xO4+δ series are single-phase in the range of x from 0.0 to 0.06 and exhibit an orthorhombic structure with a Fmmm space group. Results of the TGA-DSC studies shows that the temperature of the Fmmm – I4/mmm phase transition changes insignificantly (up to ∼5 °C), thus does not depend on Ni non-stoichiometry. The Raman scattering studies reveal that at low Ni deficiency the Raman spectra are typical for the Ni-stoichimetric oxidized (δ ≈ 0.2) Nd2NiO4+δ. While at the limiting value of x equal to 0.06, the lattice disorder and [NiO6] octahedral distortions reach a maximum feasibility with Ni–O1 vibrations getting involved into Raman scattering. The highest total conductivity (101 S/cm at the maximum) is observed for the sample with x = 0.02, which shows a more pronounced second-order overtone at 800–930 cm−1 in Raman scattering. This material can be recommended for further studies and possible electrochemical applications as the most prospective in the series due to its superior electrical properties.

AB - Neodymium nickelates Nd2Ni1-xO4+δ with Ni non-stoichiometry, varied in a wide x range of 0.0–0.08, are synthesized for the first time, and their properties are studied depending on the Ni content. The limit of Ni deficiency is found to reach 6%. According to the XRD data, the materials of the Nd2Ni1-xO4+δ series are single-phase in the range of x from 0.0 to 0.06 and exhibit an orthorhombic structure with a Fmmm space group. Results of the TGA-DSC studies shows that the temperature of the Fmmm – I4/mmm phase transition changes insignificantly (up to ∼5 °C), thus does not depend on Ni non-stoichiometry. The Raman scattering studies reveal that at low Ni deficiency the Raman spectra are typical for the Ni-stoichimetric oxidized (δ ≈ 0.2) Nd2NiO4+δ. While at the limiting value of x equal to 0.06, the lattice disorder and [NiO6] octahedral distortions reach a maximum feasibility with Ni–O1 vibrations getting involved into Raman scattering. The highest total conductivity (101 S/cm at the maximum) is observed for the sample with x = 0.02, which shows a more pronounced second-order overtone at 800–930 cm−1 in Raman scattering. This material can be recommended for further studies and possible electrochemical applications as the most prospective in the series due to its superior electrical properties.

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U2 - 10.1016/j.ssi.2022.116082

DO - 10.1016/j.ssi.2022.116082

M3 - Article

VL - 389

JO - Solid State Ionics

JF - Solid State Ionics

SN - 0167-2738

M1 - 116082

ER -